Adjusting tension really does start with the bobbin but without a gauge you probably won'd know it that's set correctly. Does your machine have a bobbin case or does the bobbin just drop in?
To adjust the upper tension to match the bobbin tension, this is the rule. When there are loops on the bottom of your sewing it means that the upper tension is too loose. Turn the upper tension to a higher number.
If the loops are on the top of your sewing it means that the upper tension is too tight. Turn the upper tension to a lower number.
Now, if the tension is okay during your normal sewing, just turn the upper tension back to whatever number you had it at before doing the binding.
I hope that helps.